hw/virtio/virtio-balloon.c

   1 /*
   2  * Virtio Balloon Device
   3  *
   4  * Copyright IBM, Corp. 2008
   5  * Copyright (C) 2011 Red Hat, Inc.
   6  * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
   7  *
   8  * Authors:
   9  *  Anthony Liguori   <aliguori@us.ibm.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.  See
  12  * the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include "qemu/iov.h"
  18 #include "qemu/timer.h"
  19 #include "qemu-common.h"
  20 #include "hw/virtio/virtio.h"
  21 #include "hw/i386/pc.h"
  22 #include "sysemu/balloon.h"
  23 #include "hw/virtio/virtio-balloon.h"
  24 #include "sysemu/kvm.h"
  25 #include "exec/address-spaces.h"
  26 #include "qapi/visitor.h"
  27 #include "qapi-event.h"
  28 #include "trace.h"
  29
  30 #if defined(__linux__)
  31 #include <sys/mman.h>
  32 #endif
  33
  34 #include "hw/virtio/virtio-bus.h"
  35 #include "hw/virtio/virtio-access.h"
  36
  37 #define BALLOON_PAGE_SIZE  (1 << VIRTIO_BALLOON_PFN_SHIFT)
  38
  39 static void balloon_page(void *addr, int deflate)
  40 {
  41 #if defined(__linux__)
  42     if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
  43                                          kvm_has_sync_mmu())) {
  44         qemu_madvise(addr, BALLOON_PAGE_SIZE,
  45                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  46     }
  47 #endif
  48 }
  49
  50 static const char *balloon_stat_names[] = {
  51    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  52    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  53    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  54    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  55    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  56    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  57    [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory",
  58    [VIRTIO_BALLOON_S_NR] = NULL
  59 };
  60
  61 /*
  62  * reset_stats - Mark all items in the stats array as unset
  63  *
  64  * This function needs to be called at device initialization and before
  65  * updating to a set of newly-generated stats.  This will ensure that no
  66  * stale values stick around in case the guest reports a subset of the supported
  67  * statistics.
  68  */
  69 static inline void reset_stats(VirtIOBalloon *dev)
  70 {
  71     int i;
  72     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  73 }
  74
  75 static bool balloon_stats_supported(const VirtIOBalloon *s)
  76 {
  77     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  78     return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
  79 }
  80
  81 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  82 {
  83     return s->stats_poll_interval > 0;
  84 }
  85
  86 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  87 {
  88     if (balloon_stats_enabled(s)) {
  89         timer_del(s->stats_timer);
  90         timer_free(s->stats_timer);
  91         s->stats_timer = NULL;
  92         s->stats_poll_interval = 0;
  93     }
  94 }
  95
  96 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
  97 {
  98     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  99 }
 100
 101 static void balloon_stats_poll_cb(void *opaque)
 102 {
 103     VirtIOBalloon *s = opaque;
 104     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 105
 106     if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) {
 107         /* re-schedule */
 108         balloon_stats_change_timer(s, s->stats_poll_interval);
 109         return;
 110     }
 111
 112     virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset);
 113     virtio_notify(vdev, s->svq);
 114     g_free(s->stats_vq_elem);
 115     s->stats_vq_elem = NULL;
 116 }
 117
 118 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name,
 119                                   void *opaque, Error **errp)
 120 {
 121     Error *err = NULL;
 122     VirtIOBalloon *s = opaque;
 123     int i;
 124
 125     visit_start_struct(v, name, NULL, 0, &err);
 126     if (err) {
 127         goto out;
 128     }
 129     visit_type_int(v, "last-update", &s->stats_last_update, &err);
 130     if (err) {
 131         goto out_end;
 132     }
 133
 134     visit_start_struct(v, "stats", NULL, 0, &err);
 135     if (err) {
 136         goto out_end;
 137     }
 138     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 139         visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
 140         if (err) {
 141             goto out_nested;
 142         }
 143     }
 144     visit_check_struct(v, &err);
 145 out_nested:
 146     visit_end_struct(v);
 147
 148     if (!err) {
 149         visit_check_struct(v, &err);
 150     }
 151 out_end:
 152     visit_end_struct(v);
 153 out:
 154     error_propagate(errp, err);
 155 }
 156
 157 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 158                                             const char *name, void *opaque,
 159                                             Error **errp)
 160 {
 161     VirtIOBalloon *s = opaque;
 162     visit_type_int(v, name, &s->stats_poll_interval, errp);
 163 }
 164
 165 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 166                                             const char *name, void *opaque,
 167                                             Error **errp)
 168 {
 169     VirtIOBalloon *s = opaque;
 170     Error *local_err = NULL;
 171     int64_t value;
 172
 173     visit_type_int(v, name, &value, &local_err);
 174     if (local_err) {
 175         error_propagate(errp, local_err);
 176         return;
 177     }
 178
 179     if (value < 0) {
 180         error_setg(errp, "timer value must be greater than zero");
 181         return;
 182     }
 183
 184     if (value > UINT32_MAX) {
 185         error_setg(errp, "timer value is too big");
 186         return;
 187     }
 188
 189     if (value == s->stats_poll_interval) {
 190         return;
 191     }
 192
 193     if (value == 0) {
 194         /* timer=0 disables the timer */
 195         balloon_stats_destroy_timer(s);
 196         return;
 197     }
 198
 199     if (balloon_stats_enabled(s)) {
 200         /* timer interval change */
 201         s->stats_poll_interval = value;
 202         balloon_stats_change_timer(s, value);
 203         return;
 204     }
 205
 206     /* create a new timer */
 207     g_assert(s->stats_timer == NULL);
 208     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 209     s->stats_poll_interval = value;
 210     balloon_stats_change_timer(s, 0);
 211 }
 212
 213 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 214 {
 215     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 216     VirtQueueElement *elem;
 217     MemoryRegionSection section;
 218
 219     for (;;) {
 220         size_t offset = 0;
 221         uint32_t pfn;
 222         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 223         if (!elem) {
 224             return;
 225         }
 226
 227         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 228             ram_addr_t pa;
 229             ram_addr_t addr;
 230             int p = virtio_ldl_p(vdev, &pfn);
 231
 232             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 233             offset += 4;
 234
 235             /* FIXME: remove get_system_memory(), but how? */
 236             section = memory_region_find(get_system_memory(), pa, 1);
 237             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 238                 continue;
 239
 240             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 241                                                pa);
 242             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 243                should be OK because we only want a single page.  */
 244             addr = section.offset_within_region;
 245             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 246                          !!(vq == s->dvq));
 247             memory_region_unref(section.mr);
 248         }
 249
 250         virtqueue_push(vq, elem, offset);
 251         virtio_notify(vdev, vq);
 252         g_free(elem);
 253     }
 254 }
 255
 256 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 257 {
 258     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 259     VirtQueueElement *elem;
 260     VirtIOBalloonStat stat;
 261     size_t offset = 0;
 262     qemu_timeval tv;
 263
 264     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 265     if (!elem) {
 266         goto out;
 267     }
 268
 269     if (s->stats_vq_elem != NULL) {
 270         /* This should never happen if the driver follows the spec. */
 271         virtqueue_push(vq, s->stats_vq_elem, 0);
 272         virtio_notify(vdev, vq);
 273         g_free(s->stats_vq_elem);
 274     }
 275
 276     s->stats_vq_elem = elem;
 277
 278     /* Initialize the stats to get rid of any stale values.  This is only
 279      * needed to handle the case where a guest supports fewer stats than it
 280      * used to (ie. it has booted into an old kernel).
 281      */
 282     reset_stats(s);
 283
 284     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 285            == sizeof(stat)) {
 286         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 287         uint64_t val = virtio_tswap64(vdev, stat.val);
 288
 289         offset += sizeof(stat);
 290         if (tag < VIRTIO_BALLOON_S_NR)
 291             s->stats[tag] = val;
 292     }
 293     s->stats_vq_offset = offset;
 294
 295     if (qemu_gettimeofday(&tv) < 0) {
 296         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 297         goto out;
 298     }
 299
 300     s->stats_last_update = tv.tv_sec;
 301
 302 out:
 303     if (balloon_stats_enabled(s)) {
 304         balloon_stats_change_timer(s, s->stats_poll_interval);
 305     }
 306 }
 307
 308 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 309 {
 310     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 311     struct virtio_balloon_config config;
 312
 313     config.num_pages = cpu_to_le32(dev->num_pages);
 314     config.actual = cpu_to_le32(dev->actual);
 315
 316     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 317     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 318 }
 319
 320 static int build_dimm_list(Object *obj, void *opaque)
 321 {
 322     GSList **list = opaque;
 323
 324     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
 325         DeviceState *dev = DEVICE(obj);
 326         if (dev->realized) { /* only realized DIMMs matter */
 327             *list = g_slist_prepend(*list, dev);
 328         }
 329     }
 330
 331     object_child_foreach(obj, build_dimm_list, opaque);
 332     return 0;
 333 }
 334
 335 static ram_addr_t get_current_ram_size(void)
 336 {
 337     GSList *list = NULL, *item;
 338     ram_addr_t size = ram_size;
 339
 340     build_dimm_list(qdev_get_machine(), &list);
 341     for (item = list; item; item = g_slist_next(item)) {
 342         Object *obj = OBJECT(item->data);
 343         if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) {
 344             size += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
 345                                             &error_abort);
 346         }
 347     }
 348     g_slist_free(list);
 349
 350     return size;
 351 }
 352
 353 static void virtio_balloon_set_config(VirtIODevice *vdev,
 354                                       const uint8_t *config_data)
 355 {
 356     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 357     struct virtio_balloon_config config;
 358     uint32_t oldactual = dev->actual;
 359     ram_addr_t vm_ram_size = get_current_ram_size();
 360
 361     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 362     dev->actual = le32_to_cpu(config.actual);
 363     if (dev->actual != oldactual) {
 364         qapi_event_send_balloon_change(vm_ram_size -
 365                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 366                         &error_abort);
 367     }
 368     trace_virtio_balloon_set_config(dev->actual, oldactual);
 369 }
 370
 371 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 372                                             Error **errp)
 373 {
 374     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 375     f |= dev->host_features;
 376     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 377     return f;
 378 }
 379
 380 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 381 {
 382     VirtIOBalloon *dev = opaque;
 383     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 384                                              VIRTIO_BALLOON_PFN_SHIFT);
 385 }
 386
 387 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 388 {
 389     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 390     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 391     ram_addr_t vm_ram_size = get_current_ram_size();
 392
 393     if (target > vm_ram_size) {
 394         target = vm_ram_size;
 395     }
 396     if (target) {
 397         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 398         virtio_notify_config(vdev);
 399     }
 400     trace_virtio_balloon_to_target(target, dev->num_pages);
 401 }
 402
 403 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 404 {
 405     virtio_save(VIRTIO_DEVICE(opaque), f);
 406 }
 407
 408 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 409 {
 410     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 411
 412     qemu_put_be32(f, s->num_pages);
 413     qemu_put_be32(f, s->actual);
 414 }
 415
 416 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 417 {
 418     if (version_id != 1)
 419         return -EINVAL;
 420
 421     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 422 }
 423
 424 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 425                                       int version_id)
 426 {
 427     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 428
 429     s->num_pages = qemu_get_be32(f);
 430     s->actual = qemu_get_be32(f);
 431
 432     if (balloon_stats_enabled(s)) {
 433         balloon_stats_change_timer(s, s->stats_poll_interval);
 434     }
 435     return 0;
 436 }
 437
 438 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 439 {
 440     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 441     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 442     int ret;
 443
 444     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 445                 sizeof(struct virtio_balloon_config));
 446
 447     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 448                                    virtio_balloon_stat, s);
 449
 450     if (ret < 0) {
 451         error_setg(errp, "Only one balloon device is supported");
 452         virtio_cleanup(vdev);
 453         return;
 454     }
 455
 456     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 457     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 458     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 459
 460     reset_stats(s);
 461
 462     register_savevm(dev, "virtio-balloon", -1, 1,
 463                     virtio_balloon_save, virtio_balloon_load, s);
 464 }
 465
 466 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 467 {
 468     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 469     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 470
 471     balloon_stats_destroy_timer(s);
 472     qemu_remove_balloon_handler(s);
 473     unregister_savevm(dev, "virtio-balloon", s);
 474     virtio_cleanup(vdev);
 475 }
 476
 477 static void virtio_balloon_device_reset(VirtIODevice *vdev)
 478 {
 479     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 480
 481     if (s->stats_vq_elem != NULL) {
 482         g_free(s->stats_vq_elem);
 483         s->stats_vq_elem = NULL;
 484     }
 485 }
 486
 487 static void virtio_balloon_instance_init(Object *obj)
 488 {
 489     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 490
 491     object_property_add(obj, "guest-stats", "guest statistics",
 492                         balloon_stats_get_all, NULL, NULL, s, NULL);
 493
 494     object_property_add(obj, "guest-stats-polling-interval", "int",
 495                         balloon_stats_get_poll_interval,
 496                         balloon_stats_set_poll_interval,
 497                         NULL, s, NULL);
 498 }
 499
 500 static Property virtio_balloon_properties[] = {
 501     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 502                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 503     DEFINE_PROP_END_OF_LIST(),
 504 };
 505
 506 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 507 {
 508     DeviceClass *dc = DEVICE_CLASS(klass);
 509     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 510
 511     dc->props = virtio_balloon_properties;
 512     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 513     vdc->realize = virtio_balloon_device_realize;
 514     vdc->unrealize = virtio_balloon_device_unrealize;
 515     vdc->reset = virtio_balloon_device_reset;
 516     vdc->get_config = virtio_balloon_get_config;
 517     vdc->set_config = virtio_balloon_set_config;
 518     vdc->get_features = virtio_balloon_get_features;
 519     vdc->save = virtio_balloon_save_device;
 520     vdc->load = virtio_balloon_load_device;
 521 }
 522
 523 static const TypeInfo virtio_balloon_info = {
 524     .name = TYPE_VIRTIO_BALLOON,
 525     .parent = TYPE_VIRTIO_DEVICE,
 526     .instance_size = sizeof(VirtIOBalloon),
 527     .instance_init = virtio_balloon_instance_init,
 528     .class_init = virtio_balloon_class_init,
 529 };
 530
 531 static void virtio_register_types(void)
 532 {
 533     type_register_static(&virtio_balloon_info);
 534 }
 535
 536 type_init(virtio_register_types)